1. Field of the Invention
The present invention relates to a sensor controller suitable to construct a sensing system for handling a large capacity of data including image data and waveform data.
2. Description of the Related Art
A displacement sensor using a two-dimensional image pickup device comprising a signal processing unit and a sensor head unit separated from each other as independent units is known (Japanese Unexamined Patent Publication No. 2002-357408, especially, with its FIG. 4). The sensor head includes a light projection laser diode and a CCD as a photodetector. The video signal generated based on the signal from the CCD is sent to the signal processing unit through an electrical cord. The signal processing unit includes a CPU mainly configured of a microprocessor and a FPGA (field programmable gate array) constituting a programmable logic circuit. The CPU mainly functions as a means of measurement processing and display control processing. The FPGA, on the other hand, mainly functions as a means of image processing.
A displacement sensor using a PSD (position sensing device) with a signal processing unit and a detector separated from each other as independent units is known (Japanese Unexamined Patent Publication No. 2002-286413). The detector includes a projection light source and a PSD as a photodetector. An analog detection signal is output from the PSD. This analog detection signal is sent to a signal processing unit through an electrical cord. The signal processing unit is mainly configured of a CPU with a microprocessor as a main component. The CPU calculates the distance based on the analog detection signal sent from the detector. The signal processing units are adjacently arranged and connected by a connector through a relay unit. Each signal processing unit transmits the distance data calculated by it to the adjacent signal processing unit through the connector. The adjacent signal processing unit calculates the differential distance, etc. using the distance data sent thereto and the distance data calculated by itself.
In the displacement sensor described in Japanese Unexamined Patent Publication No. 2002-357408, especially, with its FIG. 4, the signal processing unit includes the FPGA and therefore a sophisticated image processing can be carried out. In the absence of the function to transmit data between adjacent signal processing units, however, the collaborative operation between a plurality of sensor heads or signal processing units cannot be performed.
In the displacement sensor described in Japanese Unexamined Patent Publication No. 2002-286413, on the other hand, though having the data transmission function between adjacent signal processing units, this communication between CPUs is limited in transmission capacity. In the case where the data transmission in rapid cycles is desired to meet the detection period, for example, the value of the arithmetic operation result such as the calculated distance data can be sent, but not the waveform data or the image data having a large capacity.